Predictive auxiliary load management (PALM) control apparatus and method

ABSTRACT

An improved vehicle cooling system is disclosed having the capability of controlling various thermal components of the system to effectively control the heating and cooling of an engine of the vehicle based on instantaneous vehicle and ambient conditions and also based upon predictive conditions. These predictive conditions can include information about the upcoming terrain of the route along which the vehicle will travel.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application Ser.No. 60/800,634, filed May 15, 2006, which is incorporated by referenceherein.

TECHNICAL FIELD

The disclosed technology relates to controlling the operation of vehiclecomponents that add and remove heat from a thermal cooling system of avehicle to enhance the overall performance of the vehicle.

BACKGROUND

Known coolant pumps and cooling fans often run directly off an engineshaft by means of a gear mechanism or a belt drive system, and thereforemaintain a flow rate that is dependent only on the engine RPM. As aresult, in such cases the coolant pump provides a coolant flow rate thatis a function of the engine RPM and similarly the cooling fan maintainsan airflow rate which also is a function of the engine RPM. Suchtraditional cooling systems have been designed on the premise ofproviding adequate cooling to the engine in the worst-case scenarios,i.e., a fully-loaded vehicle running at peak power engine speed and highambient temperatures. However, these mechanically driven systems do nothave the ability or the intelligence to alter their operating strategyand adjust to the actual cooling requirement of the engine in a varietyof other operating situations. Thus, such known cooling systems do notprovide optimum cooling to the engine at all times, but end up eitherunder-cooling or over-cooling the engine during various on-the-roadscenarios. This behavior reduces the engine efficiency, leading tohigher fuel consumption and also adds auxiliary loads to the engine attimes when the engine does not have any spare power.

Variable flow electric coolant pumps have recently been introduced.These electric coolant pumps respond to control signals to vary the rateat which coolant flows in the cooling circuit.

OVERVIEW

In accordance with one aspect of the disclosure, one or more componentsthat impact the heating and cooling of an engine of a vehicle aredesirably operated other than being driven by a gear or drive link tothe engine. As a result, such components can be controlled regardless ofthe revolutions per minute (RPM) at which the engine is operated. Thisallows the selected components to be operated in a manner that moreeffectively controls the temperature of the engine. For example, theengine can be operated at or near its maximum operating temperature forlonger periods of time for more efficient operation and fuel savings.

As another aspect of this disclosure, future engine heating and coolingrequirements can be predicted based, for example, in part on knowledgeabout elevation changes in the upcoming terrain that the vehicle willencounter. As a result, vehicle heating and cooling components can beoperated in a manner that anticipates future variations in engineheating and cooling arising from changes in the terrain.

As yet another aspect of the disclosure, future engine heating andcooling requirements can be predicted based, for example, in part onknowledge about environmental conditions, such as upcoming traffic orroadwork (e.g., slow downs) that the vehicle will encounter. As aresult, vehicle heating and cooling components can be operated in amanner that anticipates future changes in traffic, roadwork or otherenvironmental conditions.

As another aspect of the disclosure, thermal components of a vehicle canbe operated so as to optimize a cost function.

In accordance with one aspect of an embodiment, knowledge of upcominghills can be utilized to control components to increase the cooling ofliquid coolant in a vehicle thermal cooling system prior to encounteringsuch hills to thereby minimize the operation of heavy power utilizingcomponents, such as an engine fan, at times when the power isparticularly needed, such as when the vehicle is climbing a hill.

As another aspect, knowledge of the terrain can be used, for example, incontrolling engine cooling components, such as a fan, to selectivelydelay their operation when the vehicle is, for example, about toapproach the crest of a hill under conditions where the temperature ofliquid coolant will remain below a maximum allowable coolant temperaturewithout the fan being turned on and even though the AC activationtemperature will exceed a set point that would otherwise result in thefan being turned on in absence of the terrain information.

In one approach, a typical land vehicle can be viewed as having amechanical power train system and a thermal cooling system. Themechanical power train system typically comprises the engine and drivetrain. The thermal cooling system typically comprises the engine (whichheats up as the engine is operated), a coolant thermostat, a radiator, acoolant pump, an engine fan and an oil cooler. Other components that addor remove heat from liquid coolant circulating in the thermal coolingsystem can also be viewed as part of such a vehicle thermal coolingsystem. For example, an engine compression brake or retarder, with ajake brake being one specific example, can add heat to the coolant whenoperated. As another example, in newer engines, exhaust gasrecirculation (EGR) systems can be utilized to cool exhaust gases forinjection as part of the charge air to the engine. EGR cooling, to theextent liquid coolant circulating in the thermal cooling system is usedto cool these recirculating exhaust gases, add to heat in the system. Asanother example, vehicle front closing mechanisms, such as shutters, canbe utilized to close off a grille or other bumper and vehicle openingsin whole or in part. When entirely closed, ambient air flow through thegrille and radiator is reduced, thereby increasing heat retention by thesystem. Also, components such as a charge air cooler and airconditioning condenser are often positioned to intercept air flowingthrough the grille which can, for example, add heat to the air whichthen impacts the extent such air removes heat when impacting a vehicleradiator. Also, a cab heater and/or sleeper compartment or bunk heater,when activated, can deliver heat from liquid coolant to the cab or otherinterior compartments of a vehicle, constituting another source of heattransfer.

As mentioned above, by replacing one or more of the components (otherthan the engine) included in the thermal cooling system withcontrollable counterparts, additional control of the thermal conditionsof the engine of the land vehicle can be achieved. For example,components can be used that are controlled other than being directlydriven by the engine. As specific examples, one or more electric poweredand electrically controlled components can be used, such as an electriccoolant pump, an electric coolant thermostat, an electric oilthermostat, an electric fan, electric motor controlled shutters, anelectric cab heater valve, and an electric cab bunk heater valve. Thesecomponents can be controlled based on instantaneous vehicle operatingconditions (including environmental conditions) or in a predictivemanner based, for example, on future elevation information along variouspoints along which the vehicle will be traveling.

Desirable aspects of various embodiments of the disclosure achieve oneor more of the following advantages, and most desirably all of suchadvantages.

1. To utilize future elevation information, as such as from a 3-D map,and current position information (such as derived from a globalpositioning satellite and vehicle speed or from an initial maneuveringunit (IMU) that computes a new position from a last known (e.g., GPSdetermined) position), to improve thermal energy management and, as aresult, to save fuel.

2. To minimize the energy consumed by engine auxiliaries, such as anengine fan and coolant pump.

3. To reduce the duration of engine cold start by rapidly bringing theengine to desired thermal operating conditions (e.g., by routing coolantin a bypass loop when the engine is cold and by initially reducingcoolant flow rates through the engine to a minimum flow rate as theengine warms up). The duration of engine cold start can also be reducedby closing air flow passageways leading to an engine compartment, suchas through a vehicle grill. A shutter or other closure mechanism can beused to accomplish this.

4. To optimize the engine thermal behavior by maintaining a high enginetemperature even during low-load operating conditions.

5. To maintain engine temperatures and coolant temperatures belowmaximum levels, such as specified by engine manufacturers, at all times.

6. To reduce internal friction due to oil viscosity and to providelubricity improvements arising from enhanced engine oil temperaturecontrol.

7. To minimize overshoot coolant temperatures at engine startup, and toachieve more stable non-oscillating coolant temperature behaviors duringoperation of the vehicle.

8. To provide a system which enhances the achievability of desirable cabtemperatures.

In accordance with an aspect of an embodiment, in the absence of vehicleposition information, in the absence of operation of the vehicle underpredictive conditions (e.g., cruise control is not being used and/or adriver predictive model is not available for the driver), and/or in theabsence of future elevation information concerning the route beingtraveled, the PALM system can control the thermal cooling systemcomponents based on instantaneous vehicle operating conditions.

In accordance with yet another aspect, of an embodiment, an optimizeddesired engine temperature profile is computed for a given load profile.The optimized engine temperature profile can be established to, forexample, minimize fuel and improve thermal efficiency. In a particularlydesirable approach, the optimized engine temperature profile ismathematically determined to optimize a cost function.

In accordance with a specific aspect of one embodiment, in the absenceof a change in elevation along the route, the PALM system can cause thevehicle to operate so as to maintain a maximum allowable enginetemperature to thereby improve engine efficiency.

As one specific approach relating to the use of terrain information,PALM establishes a look-ahead window (prediction horizon) and uses 3-Dmaps and information about the present vehicle position to establish thegrade across the positions in the window. Based in part on the gradeinformation, and starting from the current position and also based oncurrent environmental and vehicle conditions, in a desirable approachthe PALM system determines the engine heat rejected as a function acrossall positions in the window. For example, the engine heat rejection canbe determined as a function of the engine speed and engine torque. ThePALM system then can determine desired optimized engine temperatures andcontrol inputs for the various thermal impacting components to meet thecontrol system objectives. The control inputs can then be set ascommands to components, e.g., to electrically operating components, ofthe vehicle thermal cooling system.

In accordance with a desirable embodiment of the PALM system, the systemcan, in one aspect of an embodiment, ensure that engine temperatures areat a high value at the top of a hill, without exceeding the maximumcoolant temperature value, because, when the vehicle then travels downthe hill adequate cooling is achieved.

In accordance with yet another aspect of one embodiment, desirably thePALM system of this embodiment ensures that the engine temperature is ata low value at the foot of a hill to in effect pre-cool the engine priorto the vehicle climbing a hill. The low value being lower than the valueachieved merely by reduced heating of the vehicle when travelingdownhill. For example, a cooling pump can be operated at a high rate,and a fan can potentially operate, when the vehicle is travelingdownhill even through coolant temperatures are below the levels thatwould cause the operation the coolant pump at a high rate or operationof the fan in the absence of knowledge concerning the upcoming hill. Inas much as engines generate more heat when climbing a hill, thispre-cooling minimizes the possibility of coolant temperatures reachinghigh values that would require additional cooling, such as by turning ona fan, when the vehicle climbs the hill.

In accordance with a specific aspect of an embodiment, the PALM systemdesirably utilizes a cost function approach, with individual costfunctions, that is minimized, for example by minimizing the sum of suchcost functions.

The disclosure is directed toward novel and non-obvious features andmethod acts both alone and in various combinations and sub-combinationsof one another. It is not a requirement that all features disclosedherein be included within a thermal control system or that alladvantages disclosed herein are met by such a system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary profile of a section of a route beingtraveled by a land vehicle, such as a truck.

FIG. 2 is a block diagram of one embodiment of a PALM control moduleincluded within a land vehicle, together with various components of thevehicle communicating with the control module by way of a vehiclecommunication databus.

FIG. 3 is a block diagram of an exemplary thermal cooling system for aland vehicle driven by an engine.

FIG. 4 is a more detailed block diagram of one exemplary form of a PALMcontroller.

FIG. 5 is an exemplary flow chart for operation of the PALM controllerof FIG. 4.

FIGS. 6-8 illustrate the exemplary operation of various exemplarythermal components of one form of a thermal cooling system of a landvehicle in response to commands from a PALM controller for variousexemplary road section profiles when such components are operated inresponse to instantaneous vehicle conditions. These figures also comparesuch operation with an exemplary operation of a system without a PALMcontroller (FIGS. 6-8 are hypothetical examples).

DETAILED DESCRIPTION

An engine cooling system provides cooling to various parts of a vehicleengine in order to maintain the engine within a safe operatingtemperature range. The fuel combustion process is highly exothermic,resulting in the release of substantial energy. A significant portion ofthat energy is transferred to the combustion chamber walls of the engineas heat. This heat has to be constantly removed from the engine so thatthe engine material temperatures do not approach or exceed thetemperature at which material fracture occurs. This task of heat removalis accomplished in an internal combustion engine by an engine coolingsystem, which transfers energy away from the engine and releases it,such as to the space within the engine compartment and to the externalenvironment. A thermal cooling system comprises the coolant fluid (anexample being a water and glycol liquid mixture), coolant pump, coolantthermostat, cooling fan, radiator and also a conduit system forcirculating the coolant. The cooling system can also include oilcoolers, an oil thermostat, and other components, such as explained inthe example of FIG. 3 below.

Fuel economy can be improved by electronically controlling a coolantpump and cooling fan operation depending on factors such as the engineand coolant temperatures. In addition, by using predictive capabilitiesto acquire knowledge of the oncoming road grade, future engine coolingrequirements can be estimated and a control strategy can be devised toachieve desirable goals, such as to minimize the fuel consumption overthe entire route traveled by the vehicle. Information on upcomingtraffic problems can also be used in embodiments as a factor consideredin the determination of future cooling requirements.

In general, given the geographic position of a vehicle along a route(latitude and longitude from, for example, position signals provided toa vehicle mounted Global Positioning Satellite (GPS) receiver), andhaving a digital map of the route including precise elevationinformation, and with the vehicle being operated under predictiveconditions, the need for operation of auxiliary components driven by anengine over a next section of the route can be predicted. Predictiveconditions include, for example, when a vehicle cruise control is inuse. As another example, predictive conditions can also include vehicleoperation by a driver having a known drive profile. As yet anotherexample, predictive conditions can include traffic conditions, such asan upcoming construction zone along flat terrain with a tightlycontrolled speed limit or an upcoming traffic slowdown. Current or realtime traffic conditions along a route can be delivered to the vehiclefor use by the system in any suitable manner, such as via a satellite orother wireless transmissions. The operation of these auxiliarycomponents can be controlled based on these predictions to, for example,achieve lower fuel consumption or to reduce coolant temperaturevarieties (e.g., to a range of from 85°-95° C. instead of a wider moretypical set point controlled range of 50°-95° C., for a 95° C. maximumcoolant temperature. The maximum coolant temperature is typically set byan engine manufacturer, with 92° to 95° C. being examples. In the eventelevation information is not available for a route or route segment, orthe vehicle is not being operated under predictive conditions,instantaneous vehicle conditions can be used to control the auxiliarycomponents.

FIG. 1 illustrates an exemplary elevation profile along a route to betraversed by a vehicle. The vehicle 10 is illustrated schematically as atruck on the route at a reference location indicated at 0.0 forconvenience. The reference location simply indicates the current orinstantaneous position (e.g., latitude and longitude) of the vehiclealong the route. The instantaneous position can be obtained utilizingGPS technology with, for example, a GPS receiver being located on thetruck to receive a GPS signal used to provide the latitude and longitudeposition.

FIG. 2 illustrates a block 12 that can comprise the GPS receiver toprovide geographic position information. Position signals can becommunicated from block 12 to a conventional vehicle communications bus14 and from the bus to a predictive auxiliary load management (PALM)control module 16 that can control the operation of the engineauxiliaries based on calculations from input information.

A three dimensional map database 20 can be provided that can storelongitude and latitude information as well as precisely determinedelevation information corresponding to the longitude and latitudelocation. Thus, assuming the information is available for a given route,or route segment, the 3D database can contain data that includeselevation information corresponding to contour changes along the routecorrelated to the position along the route. The map database can begenerated in any convenient manner. For example, a truck or othervehicle with a pressure sensor can be driven over a route with databeing sampled (e.g., every 40 milliseconds) to provide accurateelevation information. More frequent samples can be taken, with lessdistance between data points, when elevation is changing and lessfrequent samples can be taken when elevation is relatively unchanged. Anexemplary elevation profile provides accurate elevation informationwithin one percent. The test vehicle can be driven over the routemultiple times with the results being averaged or otherwise combined toprovide more accurate elevation information for the route.Alternatively, the data can be gathered by one or more trucks travelingover a given route. When a desired number of trips have occurred overthe given route, the data may be combined, such as by averaging, tocreate the route contour. In addition, although GPS supplied elevationinformation is insufficiently accurate at this time, eventually GPSgenerated location data and elevation profiles may become accurateenough for use by the system.

With reference to FIG. 2, the exemplary block 12 comprises a GPSreceiver that receives GPS signals from which the latitude and longitudeof the instantaneous vehicle position can be obtained or computed. Inaddition, block 12 can also comprise an air temperature sensor andpressure sensor for respectively determining the ambient air temperatureoutside the vehicle at the instantaneous vehicle location and the airpressure at such location. Ambient air temperature can be used incalculating anticipated cooling requirements of the engine because moreengine cooling is typically required at higher ambient air temperatures.In addition, ambient pressure measurements provide an indicator of thedensity of air and can impact heat transfer from the engine.

These signals can be communicated to a vehicle databus 14. The PALM 16receives these signals from the databus for use in calculating theanticipated operation of engine auxiliaries, such as cooling componentsof the engine. Signals from sensors for other input devicescorresponding to a variety of current vehicle conditions, indicated atblock 18, are communicated to the vehicle communication bus and thus arealso available to PALM control module 16. A list of exemplaryinstantaneous vehicle conditions comprises fuel rate, engine torque,throttle status, wheel speed, engine rpm, gear clutch status, enginebrake level, retarder [additional optional brake] level, service brakelevel, coolant temperature, steering status, engine fan status, airconditioning (AC) status and cabin status (e.g., cab and sleepertemperature).

Engine auxiliaries can include devices that are directly connected to orcoupled to the engine shaft and that take power away from the enginesuch as an engine driven fan and gear driven cooling pump. Electricallycontrolled components are alternatives to one or more of these enginedriven components (see block 30 in FIG. 2). Also desirably included inthis engine auxiliary category are components that impact the cooling ofthe vehicle, such as shown in block 32 of FIG. 2. For example, acontrollable thermostat can be opened to permit the flow of coolantthrough the engine cooling system, thereby effecting whether a coolingfan needs to be turned on. The term thermal components comprisescomponents that add heat to or remove heat from liquid coolantcirculating in a cooling system of the vehicle. Thermal components alsocan comprise non-passive components that operate to assist in theremoval of heat from or retention of heat by the vehicle cooling system.FIG. 3, described below, illustrates exemplary thermal components of avehicle. In addition, the reference to a selective front opening closuremechanism or shutter refers to, for example, a device that is operableto partially or entirely close off grille and/or bumper openings of avehicle when cooling requirements are reduced. In contrast, suchopenings can be partially or fully opened to assist in cooling of thevehicle by permitting maximum air flow through such openings to theengine compartment of the vehicle when greater engine cooling isrequired.

Signals corresponding to the operating condition of these engineauxiliaries 34 are desirably provided to vehicle communication bus 14and are thus available to the PALM control module. In addition, thesevarious components can be controlled by signals from the PALM controlmodule (e.g., whether the coolant thermostat is opened, the selectivefront opening closure mechanisms being open or closed, the fan beingturned on or off, the coolant pump being operated and controlled tocirculate more or less coolant, etc.). In the case of an electriccoolant pump with a variable flow rate, PALM can desirably control theRPM of the electric coolant pump to vary the flow rate from a minimumcoolant flow rate to a maximum flow rate. As an example, and not arequirement, one suitable electrical variable flow rate coolant pump isproduced by Engineered Machine Products, Inc. of Escanaba, Mich.

The map module 36 in FIG. 2 can be provided with knowledge of theinstantaneous position of the vehicle (from signals on the data bus orfrom a map request from PALM) and can fetch data from the 3D MAPdatabase corresponding to an upcoming section of a route or expectedroute (e.g., the next two to five miles). This upcoming route sectioncan be termed a prediction horizon. If the GPS location or positionsignal indicates the vehicle has deviated from the expected routesection (e.g., taken a freeway exit), a new expected route section canbe selected as the next prediction horizon or window. Respective windowscan be opened to correspond to successive or otherwise selected routewindows such that route information processing can be accomplishedsimultaneously in more than one such window.

The window or route segments need not be a constant length, althoughthis can be desirable. For example, when traveling over terrain known tobe substantially flat (e.g., portions of Nebraska), PALM can selectwindows of extended length. Alternatively, instantaneous conditions canbe used for control of the thermal components in such cases rather thanusing PALM calculations for control. The PALM control module can thenpredict the anticipated engine cooling requirements that will arise asthe vehicle traverses this upcoming section of the route and can computea set of control signals to alter the control of the engine auxiliariesto improve the performance of the vehicle, such as to increase the fuelefficiency or to maintain the engine temperature at a high level toenhance engine performance. Desirably, the map module 36 retrievesupcoming prediction window as data related to the just traversedprediction window is discarded so that calculations can be made rapidlyon an ongoing basis.

A number of examples of how the PALM system can operate are describedbelow. For example, assume the vehicle 10 reaches location x1 of FIG. 1.Also assume that the instantaneous vehicle conditions would indicatethat no additional cooling is required. Thus, the coolant thermostatcan, for example be closed (coolant temperature is below a set point)and a grille closure mechanism is closed. In the absence of thepredictive element of the PALM system, the vehicle would continue tooperate under this mode as it reaches the next hill (it starts atroughly the 0.5 mile point in FIG. 1). As the vehicle goes up the hill,increased cooling is required with the thermostat being opened, forexample, the coolant pump being operated at an increased rate; and thevehicle fan turning on.

In contrast, in situations where elevation data is known for an upcomingsection of a route, because the PALM system knows that a hill will soonbe reached, at X₁ (or some other location prior to the hill), thecoolant thermostat can be opened and the grille cover opened to increasecooling before the hill is reached. If sufficient pre-cooling isachieved, the possibility exists of not having to operate the coolantpump at high speeds or, if the cooling pump is operated at high speeds,in contrast to a minimum rate, not having to turn on the vehicle coolingfan. In a heavy duty truck, a belt driven cooling fan can use up toabout ten to fifteen percent of the engine power when on. In contrast, agear driven cooling pump driven by an engine drive shaft or by analternator, can utilize two to three percent of the engine power. Thus,it is desirable to pre-cool the engine to minimize the possibility ofthe fan turning on or to limit the amount of time the fan is on. In thecase of an electrically controlled variable speed coolant pump and anelectric cooling fan, it can be desirable to minimize the rate ofoperation of the coolant pump and to minimize the operation of a fan,for example to save the energy required to operate the pump at highrates and to operate the fan.

When the vehicle reaches location X₂, instantaneous conditions mayindicate that the cooling fan should be turned on. However, because thecontour of the route is known in this example, and therefore the factthat the vehicle is almost at the crest of the hill is known, PALM cancontrol the system to prevent the fan from turning on as cooling willincrease without the fan as the vehicle crests the hill and travelsdownhill.

Similarly, at location X₃ because the upcoming contour is known in thisexample, even though the vehicle is descending, the PALM systemrecognizes that a hill is approaching. Therefore, at X₃ steps can betaken to increase the pre-cooling of the engine in advance of the hill(e.g., the thermostat can be open, grille closure mechanisms can beopen). Similarly, at X₄, PALM recognizes that a significant portion ofthe hill remains and can control the cooling pump to increase the flowof cooling fluid, thereby deferring or delaying the turning on of thefan.

As another example, the PALM controller can calculate the future engineand cooling system requirements for the upcoming prediction horizon orwindow. Auxiliaries can be intelligently controlled to maintain anoptimal engine temperature along the route at which the engine operatesat maximum thermal efficiency. Some exemplary scenarios are as follows:

-   -   Knowing an uphill is coming ahead, the controller can increase        the cooling pump speed of a variable speed coolant pump before        the uphill section to enhance cooling of the coolant so as to        avoid or minimize the turning on of the controlled engine        cooling fan    -   Knowing a downhill is coming ahead and the vehicle on the        downhill portion will be accelerated, so the cooling will be        more intense than necessary, the controller can reduce the speed        of the controlled coolant pump. The commands to the controlled        coolant pump are desirably coordinated with commands to a        controlled coolant valve and controlled front grille blinds.    -   The engine cooling fan can be triggered by operation of a        vehicle AC system. This can happen when approaching the top of        an uphill section. However, by knowing the distance and time        required to reach the top of the uphill section, the controller        can determine that the operation of the fan can be delayed        (e.g., because cab and bunk temperature are not expected to        become uncomfortable before the top of the hill is reached) even        though AC operation commands indicate the fan should be turned        on.

The engine cooling requirements for achieving a desired enginetemperature profile along a route are desirably translated by thecontroller into command signals to the controlled components, such asthe engine cooling fan, controlled cooling valve, controlled coolingpump and other controlled thermal system cooling components. Thecommands are sent to the controlled auxiliaries, such as via the vehiclecommunication bus, via hardwired communication lines, or by wirelesscommunication.

A computer model has been developed to simulate the combustion and heatexchange processes in a turbocharged direct-injection diesel engine. Onecan estimate the engine heat rejection based on a model for the energyrelease process of combustion. The coolant flow through the engine blockcan be modeled to calculate the heat removed from the engine.

Due to a constantly changing road profile and vehicle power requirementsfor any actual on-the-road situation, the engine operating conditionsand temperatures are always in a transient state and never reach asteady state value. To accurately simulate such dynamic situations, itis desirable that the entire coolant flow circuit comprising theradiator, pump, coolant thermostat and hoses be modeled. Since, thecoolant ultimately transfers the heat to the engine compartment orambient air, the model can also include the airflow circuit comprisingthe cooling fan, charge air cooler, AC condenser and grille assembly,grille closing (shutter) assembly, if any, as well as other components.

The forces opposing the motion of a vehicle on a flat road can bebroadly classified into two categories: aerodynamic resistance, andfriction resistance. For the vehicle to maintain its motion, the enginemust provide sufficient power to overcome these forces. When atransmission is engaged, the engine RPM can be directly proportional tothe vehicle speed with the power train overall ratio being the constantof proportionality. In a directly driven cooling system (e.g., a coolantpump driven by a gear from an engine drive shaft), the cooling systemoperation is directly linked to the engine RPM. The higher the engineRPM, the greater the coolant flow rate generated by the pump and thegreater the airflow rate generated by a direct driven cooling fan whenswitched on. Consequently, in such an approach, at a higher vehiclevelocity, the amount of cooling provided to the engine is greater.

Consider a scenario where the vehicle is traversing a positive roadgrade. The weight of the vehicle adds another force opposing the vehiclemotion, and this is commonly termed as road grade resistance. Under sucha situation, the engine has to generate a higher power in order tomaintain vehicle motion. This causes the engine temperatures to rise,which can result in the cooling fan being turned on. A direct drivecooling fan can consume on average 10% to 15% of the engine power. Ineffect, when the fan turns on, the cooling system uses significantengine power at a time when that power is needed to maintain the vehiclespeed. In such a situation, the vehicle may not be able to maintain itsspeed and can slow down.

The above analysis demonstrates how the operation of the cooling systemat a critical time can affect the engine output power available to drivethe vehicle. In a direct drive cooling system, as explained above, boththe coolant and air flow rates can be directly proportional to theengine RPM. For the case where the vehicle is traveling uphill, sincethe RPM is lowered, this can mean that the coolant and air flow rateswould be reduced. Therefore, in spite of the fact that the enginetemperature is now higher as compared to the engine temperature when thevehicle is on a flat road, the cooling being provided to the engine hasbeen reduced. Even if the RPM were to be maintained at the same value asthat on the flat road, the cooling provided to the engine while goinguphill would at best be equal to the cooling provided on the flat road.If one assumes that the cooling provided to the engine in the case of aflat road is sufficient, this implies that the cooling provided to theengine for an uphill road would be less than what is required; asituation termed as under-cooling. However, if one assumes that thecooling during the uphill condition is sufficient, then the cooling onthe flat road is greater than what was required; a situation termed asover-cooling. A similar analysis can be done to compare the performanceof the cooling system between a downhill road and a flat road, and wouldlead to analogous conclusions.

Consider a situation where the vehicle is traveling uphill and thecooling fan is turned on just before reaching the summit. The coolingfan has a significant inertia associated with it, and, in order to avoidconstant on-off operation for the fan, a cooling fan is commonlydesigned such that, once it is turned on, it remains on for some amountof time. If the fan control is based at least in part on future roadinformation, one can potentially avoid turning on the fan just before asummit, since beyond the summit the fan would not be required as theengine temperature itself would fall due to lower power requirements. Inaddition, when a vehicle is traveling on a downhill grade, thecontroller can activate the fan and provide an “active-braking”function, while still meeting the engine cooling requirements.

Thus, a cooling system having an operation governed by only the engineRPM is not an optimum solution. A cooling system can be more efficientif controlled under certain conditions based upon upcoming coolingrequirements. Efficiencies can also be achieved by embodiments utilizingcooling components (e.g., a coolant pump) that are not driven directlyby a gear or other connection to an engine drive shaft.

Modeling Methodology

Although the system in one embodiment desirably operates based uponcomputing heat transfer characteristics of the system, otherapproximations can be used. Also, refinements to and alternative formsof modeling and heat transfer computations can be used.

In one exemplary approach, a simulation models the engine, the coolantcircuit and the cooling airflow. The engine is the primary source ofheat to be removed. In this model, it is assumed that the cold coolantenters the engine block from the bottom and exits through the top or thehead of the engine block. While passing through the engine, the coolantpicks up heat from the engine block walls and head.

The complete diesel combustion cycle, in this specific exemplaryapproach, was modeled at crank-angle time intervals to determine thetemperature and pressure of the gas mixture. The engine cylinder modelwas divided into different control volumes (CVs). Mass and energybalance principles were used to compute the work done and the heattransfer from the combustion gases to the engine chamber. The unsteadyform of the first law of thermodynamics was applied to each controlvolume in terms of the control volume temperature, net enthalpy efflux,radiation and convection heat transfer, and stored energy resulting in aset of time dependent differential equations. These differentialequations were then solved to obtain the control volume temperatures.

Mass flow rates through the intake and exhaust valves were calculated inthis exemplary approach using the equation for compressible flow througha restriction, derived from a one-dimensional isentropic flow exemplaryanalysis. The single-zone model of combustion was chosen for theanalysis. Heat release due to combustion was modeled in this example asconsisting of two different modes of fuel burning: a rapid premixedburning phase followed by a slower mixed-controlled burning phase. Inthe exemplary approach, the fraction of the injected fuel that burns ineach of these phases was empirically linked to the ignition delay time.

An exemplary heat transfer model has been developed to calculate theheat transfer from the in-cylinder gases to the engine and from theengine to the coolant. During a combustion cycle, the in-cylinder gastemperature shows a huge variation. In order to accurately estimate theheat transfer from the gases to the combustion chamber walls, it isdesirable in one approach to do this heat transfer calculation at thesame time step as the combustion cycle time step. Thus, at each crankangle rotation, one exemplary model calculates the mechanical powerproduced and also the heat transfer from the gases. A cycle-by-cyclecalculation is desirably performed in this exemplary approach todetermine the heat transfer from the gases to the combustion chamber.The heat transfer is desirably integrated over the entire cycle tocalculate the total energy transfer over the combustion cycle, and thentime-averaged to determine the rate of energy transfer, (the energytransfer per unit time).

The heat transfer rate from the combustion gases to the combustionchamber depends on the temperature of both the gases and the chamberwalls. If an engine is allowed to reach a steady state operation, thewalls would reach a constant, time-invariant temperature, and only thetemperature of gases would vary during the combustion cycle. Under suchconditions, the heat transfer and engine power would have a constant,steady-state value. However, for a vehicle operating in real-life,on-the-road conditions, the equilibrium or steady-state is neverreached. This is attributed to the fact that the load on the engine,influenced by required speed and road grade and other variables,continuously changes as the vehicle is traversing a route.

To more accurately calculate the heat transfer under suchnon-equilibrium, unsteady conditions, one can use transient state heatrejection maps. These maps are used to calculate the transient heatrejection rates as a function of the temperature of the combustionchamber walls temperature. The maps have been developed to computepolynomial coefficients based on fuel rate, boost pressure, and engineRPM, and the coefficients are used to calculate the heat transfer,taking into account the instantaneous wall temperatures.

One exemplary simulation model desirably contains various routines whichsimulate the engine, radiator, charge air cooler (CAC), fan, airflowcircuit, turbocharger, coolant circuit and oil circuit. Most of thesemajor components are modeled mathematically with a transient approach topredict and represent the steady state as well as the transientoperation. The exemplary model utilizes three main run-time data,namely: the engine speed, fuel flow rate and the vehicle speed. Selectedambient conditions are also provided as input data.

The engine model is an important component since energy rejection to thecoolant and the oil comes primarily from the engine. A six cylinderdiesel engine has been modeled in one approach by assuming that all thecylinders are operated at approximately the same operating conditions,making it possible to mathematically model a single cylinder and extendthe results to the remaining cylinders. Combustion was modeled, in thisexample, as a single-zone heat release process. The gas exchange processof this example uses a one-dimensional quasi-steady compressible flowmodel. The heat transfer model of this example uses empiricalcorrelations for calculating the convective heat transfer. The radiativeheat transfer of the model was calculated on the basis of the flametemperature. The frictional model converts selected quantities (e.g.,power and indicated specific fuel consumption) to the correspondingbrake quantities. A steady-state turbocharger model, manifold heattransfer, and pressure losses were also included in the exemplarysimulation. The engine model in this example calculates the surfacetemperatures and mass-average temperatures for the piston, cylinder headand liner, and the exit temperatures of the coolant and the oil.

An exemplary coolant system comprises the following main components:coolant pump, cab heater, bunk or sleeper heater (if the vehicle is atruck with a separately heated bunk area), engine, oil cooler,thermostat, fan and radiator. Pressurized coolant from the pump isforced through the oil cooler and the engine. Heat rejection from theengine is the main source of energy to the coolant. A full-blocking typethermostat can be used in one example to control the flow of the coolantthrough the radiator. When the coolant temperature is below a coolantthermostat activation temperature, the closed thermostat directs all thecoolant through a bypass conduit to the coolant pump. When thethermostat opening temperature is reached, the coolant thermostat can becontrolled so as to open, resulting in coolant flow being dividedbetween the radiator and the bypass conduit.

The coolant pump circulates the coolant through the engine coolingsystem. The pump can be driven directly off the engine by means of agear mechanism. However, more desirably the coolant pump is a variablepump that operates at a rate determined by electrical control signals.Data points relating the pump flow with the engine speed can be providedby an engine manufacturer or obtained from engine bench tests. Datapoints relating the pressure loss through individual components to theflow rate can also be obtained in the same manner. A pump model wasdeveloped to calculate the pump flow as a function of the engine speed(for a gear driven pump). Control settings to control an electricallycontrolled cooling pump to achieve coolant flow rates corresponding torates at specific engine RPMs for a gear driven coolant pump weredetermined. The coolant pump within the cooling system was assumed tohave no affect on the fluid temperature in this example. The pumping ofa fluid through the system generates an increase in thermal energy dueto fluid friction, which is dependent on the fluid viscosity and systempressure. For an engine application, in this specific example, theseeffects can be assumed negligible in comparison to the thermal energytransferred to the coolant from the engine's combustion heat transferprocess.

Major assumptions that were made in the exemplary model:

-   -   One-dimensional unsteady compressible flow for calculating mass        flow rates past the intake and exhaust valves.    -   Intake air and exhaust gases modeled as ideal gases.    -   Single-zone combustion model; cylinder charge is assumed to be        uniform in both composition and state.    -   No losses or leakage from any component in the system.    -   One-dimensional heat transfer for the cylinder liner, head and        piston.    -   Uniform surface area averaged wall surface temperature, constant        throughout a combustion cycle.    -   Mass averaged, uniform temperatures for the engine bulk        materials.

The cylinder volume was modeled as an open thermodynamic system, forintake and exhaust strokes. This was based on the assumption that at anyinstant in time, the gases inside the open system boundary have auniform composition, pressure and temperature. Mass and energyconservation equations were then used to derive the differentialequations for the rate of change of the open system's thermalproperties.

Mass Conservation: The rate of change of total mass of an open system isequal to the sum of the mass flows into and out of the system, expressedas:

$\overset{.}{m} = {\sum\limits_{j}{\overset{.}{m}}_{j}}$

Energy Conservation: The first law of thermodynamics applied to an opensystem is expressed as:

$\overset{.}{E} = {{\overset{.}{Q}}_{w} - \overset{.}{W} + {\sum\limits_{j}{{\overset{.}{m}}_{j} \cdot h_{j}}}}$

Where Q_(w) and W are the total heat transfer rate into the systemacross the boundary, and the work transfer rate out of the system. Therate of change of the system energy is expressed as:

$\frac{\mathbb{d}({mu})}{\mathbb{d}t} = {{\frac{\mathbb{d}}{\mathbb{d}t}({mh})} - {\frac{\mathbb{d}}{\mathbb{d}t}({pV})}}$

Gas Exchange Model: Valve overlap and reverse flow affects wereaccounted for in the model. Mass flow rates through the intake andexhaust valves were calculated using the equation for compressible flowthrough a restriction, derived from a one-dimensional isentropic flowanalysis. Instantaneous values of valve lift on a crank angle basis wereprovided by DDC. Knowing the valve diameter, instantaneous values ofarea, the mass flow rate was calculated at each step of the gas exchangeprocess.

Combustion Model: Diesel combustion is a complex, heterogeneous processand a comprehensive combustion analysis would require accurate models ofcompressible viscous air motion, fuel spray penetration, dropletbreak-up and evaporation, air entrainment into the spray, combustionkinetics, turbulent diffusion etc. The zero-dimensional or single zonemodel of combustion, used for the present model, does not take intoaccount atomization, liquid jet and droplet motion, fuel vaporization,air entrainment and ignition chemistry. The fuel injected into thecylinder is assumed to mix instantaneously with the cylinder chargewhich is assumed to behave as an ideal gas.

Heat Release Rate:{dot over (m)} _(t) ={dot over (m)} _(p) +{dot over (m)} _(d)where,

{dot over (m)}_(p)=premixed burning rate

{dot over (m)}_(d)=diffusion-controlled burning rate

{dot over (m)}_(t)=apparent fuel burning rate with respect to crankangle

Ignition Delay Time:

$t_{D} = {{Ap}^{- n}{\exp\left( \frac{E_{A}}{RT} \right)}}$

Heat Transfer Model: The different heat transfer mechanisms dealt within the exemplary model include forced convection from the turbulent flowin the cylinder to the combustion chamber walls, forced convection fromthe cylinder walls and head to the coolant and from the piston to thecooling oil, radiation from the flame and the burning carbonaceousparticles and conduction through the combustion chamber walls.

Convective Heat Transfer: Nusselt number relations.Nu=aRe^(m)Pr^(n)

Radiative Heat Transfer:Q _(r) =Cσ(T _(g) ⁴ −T _(w) ⁴)

Engine Cylinder Model: The engine cylinder model of this example wasdivided into eight different control volumes: cylinder liner, headsurface, piston, bulk cylinder wall, cylinder head bulk, block coolant,head coolant, and piston cooling oil. The unsteady form of the first lawof thermodynamics was applied to each control volume in terms ofmass-averaged control volume temperature, net enthalpy efflux, radiationand convection heat transfer, and stored energy resulting in a set ofeight time dependent differential equations. These differentialequations were then solved to obtain the temperatures of the engine andthe coolant.

Transient-state Heat Rejection Maps: The exemplary model captures thephysics of two distinct processes: combustion and heat transfer. Thecombustion calculations have a ‘high’ time dependency; the calculationis desirably performed at each crank angle rotation to keep track of thephysical properties of the mixture in the cylinder. On the other hand,the heat transfer model has a greater thermal inertia and desirably canbe less frequently performed, such as no more than once every second, tokeep track of the bulk temperatures. For a real-time implementation ofthe model and developing a real-time controller, it can be desirable tospeed up the calculations. A crank angle scale combustion computation isundesirably slow. Therefore, a more desirable model is based upontransient-state heat rejection maps.

The transient maps in one exemplary approach take the bulk temperatures,engine RPM, and fuel rate input at the start of every combustion cycleand compute the following cycle variables: power or useful workdelivered, bulk metal temperatures and coolant temperatures at the endof the combustion cycle. By solving the complete set of equations onlyonce every cycle in this example, the model does away with performingthe calculation multiple times (e.g., 720 times) during the combustioncycle.

The heat release rate calculation, through the maps, is dependent onlinear coefficients that vary with the engine RPM and fuel rate, and onthe material temperatures. Since, the three independent variables ofengine RPM, fuel rate, and engine temperatures can be approximated tohold constant over a cycle, a single computation per cycle can be usedand can be sufficient to capture the thermal responses of the system.

Cooling System Model: The engine is the main source of energy to thecooling system, and the rest of the components of the cooling systemensure that the engine's energy is released into the ambientsurroundings. In an exemplary system, a coolant pump maintains a closedcircuit coolant flow, a fan provides the cooling air flow, and theradiator is the primary heat exchanger that facilitates transfer ofthermal energy from the coolant to the cooling air. These componentstaken together are the major constituents of such a cooling system.Other components can also be included, such as explained below.

In the truck designs, a charge air cooler and AC condenser are typicallyinstalled in front of the radiator, in the pathway of the air flowthrough the vehicle grille. This means that the cooling air flowexchanges heat with the condenser, and with the charge air cooler, andlastly with the radiator. Thus, to model the radiator heat transfer insuch a system, it becomes desirable to account for the presence of thetwo other heat exchangers present in the air flow path. The coolant inthe radiator exchanges heat with the cooling air; this cooling air is,however, not at the ambient temperature but its temperature has beenaugmented by the heat exchange taking place in the other two heatexchangers. Additionally, the flow rate of cooling air in the presenceof these heat exchangers is less than what it would have been had theseheat exchangers been absent from the flow path. This is accuratelyunderstood and can be modeled using pressure drop versus flow ratecurves for the system and its constituent parts. For such reasons, thesimulation desirably includes thermal models for the charge air coolerand condenser as well.

Exemplary Vehicle Thermal Cooling System

FIG. 3 illustrates an exemplary thermal cooling system for a landvehicle and also illustrates a data communications bus 14 coupled tovarious sensors to receive input signals and to provide control signalsto components of the thermal system. In addition, a PALM controller 16is coupled to the databus and thus can communicate via the databus withthe various components of the thermal system. Although less desirable,the PALM controller could alternatively be hardwired directly to one ormore of the thermal components and sensors.

In FIG. 3, an engine block 100 is illustrated. The primary source ofheat in the system arises from combustion within the engine block.Coolant from engine block 100 is delivered via a conduit 102 through anoptional brake retarder 104 and a conduit 106 to a coolant thermostat108 which can be controlled between open and closed positions inresponse to control signals S_(ct) via bus 14 to a coolant thermostatcontroller 110. The coolant thermostat 108 can be a two positionthermostat (open or closed) or a variable thermostat in the sense thatit can be controlled to open varying amounts in response to the controlsignals. In the event coolant thermostat 108 is closed, a pathway existsvia a bypass conduit 116 to a coolant pump 120. When coolant thermostat108 is open, a pathway 122 is provided to a vehicle radiator 130 withcoolant passing through the radiator 130 to a conduit 132 and to thecooling pump 120. A portion of the coolant can also be simultaneouslydelivered via conduit 116 to the coolant pump 120. Depending upon theposition of coolant thermostat 108, in the case of a variable positioncoolant thermostat, all or selected portions of coolant can be deliveredvia the pathway 122 and through the radiator. The coolant pump 120 canbe driven (e.g., via a gear) by the engine for operating when the engineis running. However, more desirably, coolant pump 120 is an electricallycontrolled coolant pump capable of pumping a varied volume of coolantthrough the pump depending upon coolant pump control signals. In theembodiment of FIG. 3, coolant pump control signals S_(cp) are deliveredto a coolant pump controller 134 for controlling the coolant pump 120 tooperate at the desired rate. Typically coolant pump 120 operates at someminimal rate so that some minimal liquid coolant is recirculated in thecoolant system at all times when the engine is operating. Liquid coolantpassing through the coolant pump 120 is delivered via a conduit 140 andthrough an optional exhaust gas recirculation (EGR) cooler 142 and to aconduit 146. From conduit 146, the liquid coolant passes through an oilcooler (heat exchanger) 150 to cool engine oil. An exemplary oil coolingcircuit is explained below. The coolant passing through the oil cooler150 is delivered via a conduit 152 back to the engine block 100.

In the system of FIG. 3, a cooling fan 160 is also illustrated.Desirably the cooling fan is electrically operated by an electric motor162 in response to control signals from a fan controller 164. These fancontrol signals S_(F) are desirably provided to fan motor control 164from the databus 14. Although a variable speed fan can be used, in oneimplementation the fan is either turned on or off in response to thecontrol signals S_(F). Typically when turned on, the fan remains on fora period of time. The fan can be responsive to coolant temperature setpoints. When on, the fan assists in moving air across the radiator 130to cool the liquid coolant passing through the radiator. The exemplarysystem in FIG. 3 comprises a turbocharger and optional emission gasrecirculation (EGR) valve 170. The turbocharger provides charge air vialine 172 and through a charge air cooler 174 and a conduit 176 (B) to acharge air inlet 178 (B) to the engine block 100. At least some of thecharge air in this example is provided to the turbocharger 170 by way ofan inlet 180 (A) coupled to an outlet 182 from the EGR cooler 142 suchthat recirculating emission gases are included in the charge air in thisexample.

An air conditioning condenser 180 is also shown adjacent to the chargeair cooler and in the air flow path for receiving air (indicated byarrows 200) that has passed through a grille 202. An optional closuremechanism such as a shutter 210 is shown positioned adjacent to thegrille for selectively closing the openings through the grille and thusthe passageway for ambient air, indicated by arrows 212, impacting thetruck grille from entering the engine compartment through the grille.The shutter 210 can also selectively close other openings, such asbumper openings at the front of the truck. Control signals S_(s) aredelivered via bus 14 and to shutter controller 214 (which can control ashutter motor, not shown) for use in controlling the shutter betweenopen and closed positions, and/or between selected positionstherebetween. An exemplary shutter system is disclosed in published U.S.Patent Application 2006/0102399, Ser. No. 11/211,331, entitled SelectiveClosing of at Least One Vehicle Opening at a Front Portion of a Vehicle,to Guilfoyle et al. application Ser. No. 11/211,331 is herebyincorporated by reference herein.

The engine block 100 is schematically illustrated as including an oilsump 220 at a lower portion of the engine block. An outlet conduit fromoil sump 220 is coupled to an oil pump 222 and via an oil thermostat 224to the oil cooler 150 when the oil thermostat 224 is open. Cool oil fromoil cooler 150 is returned, via a conduit 250 to the oil sump 220. Inthe event oil thermostat 224 is closed, oil is delivered via a bypassconduit 252 to the conduit 250 and back to the oil sump. The oilthermostat 224, in this example, can be electrically controlled by wayof oil thermostat control signals S_(OT) from bus 14 delivered to acontroller 254 coupled to the oil thermostat 224. Also, the operation ofthe oil pump 222 can be controlled by oil pump control signals S_(OP)delivered from databus 14 to an oil pump controller 256. Alternatively,set points can be used to control the oil thermostat and a gear driveroil pump can be used.

In the illustrated system of FIG. 3, a simplified diagram for aninterior compartment heating system is also disclosed, such as a cabheater 260 and bunk heater 261 within the interior of a truck cab. Whena cab heater control valve 262 is open, heat containing coolant passesfrom conduit 146, through oil cooler 150, and a conduit 264 through thecab heater valve 262 to a heat exchanger comprising a portion of the cabheater. When a bunk heater control valve 263 is open, heat containingcoolant passes from conduit 146, through oil cooler 150, and a conduit265 through the bunk heater valve 263 to a heat exchanger comprising aportion of the bunk heater. One or more fans or other heat transfermechanisms may be used to transfer heat from the cab heater and bunkheater (if included) to the interior of the cab via heating ductwork orpassageways. The operation of heater valve 262 can be electricallycontrolled via heater control signals S_(H1) delivered from databus 14to a heater valve controller 270. The operation of heater valve 263 canbe similarly electrically controlled via heater control signals S_(H2)delivered from data bus 14 to heater valve controller 271.

In the embodiment of FIG. 3, many of the thermal system components aredescribed as being electrically controlled. This is a particularlydesirable approach. However, advantages can also be achieved in theevent temperature controlled thermostats are used with or without anelectrically controlled coolant pump. That is, in a predictive approachwhere terrain along a portion of the route is known and where thevehicle is being operated under predictive operating conditions, asystem can operate in the conventional manner except for delaying theoperation of the cooling fan at selected times (for example, as a crestof a hill is approaching). More desirably, at least the coolant pump,coolant thermostat and cooling fan are electrically controlled tofacilitate the passage of variable amounts of liquid coolant through theprimary coolant passageways to enhance cooling of the system either inresponse to instantaneous vehicle operating conditions or in response topredictive control based on upcoming elevation changes in the terrain.For example, additional amounts of coolant can be circulated by thecooling pump as a vehicle travels downhill to in effect increase thecooling of the liquid coolant in preparation for the vehicle climbing anupcoming hill. Also, the shutter system can be controlled to enhancecooling at desired times based on predictive or advance knowledge ofupcoming terrain changes. It should be noted that closing of the shutter210 enhances the aerodynamic efficiency of the vehicle and therebydecreases fuel usage in many instances.

In addition to the control signals previously noted, ambient conditionsand vehicle operating conditions can be sensed and converted to signalswhich are also delivered to the bus 14. Some of these signals comprisethe following: R_(AV)=RAM air velocity; FR=fuel rate; RPM=engine rpm;T_(A)=temperature/ambient; P_(A)=pressure/ambient; T_(CA)=temperaturecharge air (at turbocharger 170 outlet); and T_(CEO)=temperature ofcoolant at the engine output (e.g., at entrance to conduit 102).

These signals can be used in a desirable embodiment to calculate theamount of heat transfer for removal by the cooling system to achieve adesired temperature profile for the engine operating under predictiveoperating conditions as it travels along future portions of a route.Various control signals can be generated to cause the engine to operateso as to have a temperature that follows the optimum temperature profileto thereby achieve benefits, such as to optimize a cost function.

FIG. 4 illustrates a block diagram of one form of a PALM controller 16in accordance with the disclosure. The illustrated PALM controller 16comprises a position estimator 300 operable to compute the position ofthe vehicle at a given instant in time. Desirably, the vehicle isequipped with a position sensor such as a GPS receiver for receiving aGPS signal indicative of the position of the vehicle, such as bylongitude and latitude. The GPS signal, or a representation thereof, isdelivered via a line 302 to one input 303 of the position estimator. Inaddition, the current vehicle velocity, or data from which the velocitycan be calculated, is delivered via a line 304 to another input 305 ofthe position estimator. From this data the position estimator cancompute the current position of the vehicle and estimate when thevehicle will reach future positions. The controller 16 also comprises anoptimizer 320, that can comprise a programmable controller having aprocessor and associated memory. The controller can be pre-programmed orcan be provided with an input, such as for receiving original and/orupdated programming instructions via the databus 14.

One or more inputs can be provided to the optimizer 320. For example,the current velocity can be provided at an input 322 and map data can beprovided at an input 324. Typically, the map data provides elevationinformation for upcoming portions of the route and can be searched insegments based upon the estimated position of the vehicle. Vehicleparameter information can be provided at an input 326 to the optimizer320. For example, vehicle conditions, such as indicated in FIG. 3 (e.g.,condition of coolant pump, condition of fan, condition of shutters,charge air temperature, and so forth). Environmental conditions can alsobe provided via an input 328, such as the ambient temperature andambient pressure information. The data provided to the optimizer 320 isnot limited to these specific data inputs as represented by an input 332labeled as “Other” in FIG. 4. For example, traffic information (e.g., anupcoming traffic slowdown, road repair slowdown) can be provided. Asanother example, a driver profile can be provided for the vehicledriver, if available, that can be used in predicting how a truck will beoperated by the profiled driver over a road section in the event cruisecontrol is off.

The optimizer 320 can operate in a number of different modes. Forexample, assuming both the map data and position indicating informationis available, and the vehicle is being operated under predictiveconditions, the optimizer 320 can operate as a predictive controller.For example, from the available information, the optimizer 320 cancompute a desired engine temperature profile and deliver this profilevia an output 350 to an instantaneous controller 360. For example, thedesired temperature profile can be based on the temperature that theengine is allowed to reach at various points along the route in a mannerthat minimizes a cost function (for example limiting the turning on ofthe vehicle fan). A temperature profile can be computed based onestimating the heat transfer required for the vehicle to operate at thedesired engine profile corresponding to locations along the route. Theinstantaneous controller 360 then determines and provides control inputsto the databus 14 for controlling various components of the vehicle sothat the vehicle is operated in a manner that causes the enginetemperature to follow the determined temperature profile. These controlinputs can, for example, include control signals for the electriccoolant pump; electric coolant thermostat; electric oil thermostat;electric fan; electric shutters; and electric cab heater valve in theevent electrically controlled components are used for these elements ofthe vehicle thermal system. These control inputs are provided via a line370 to the databus. In the event the map data and/or the GPS signal orposition information is unavailable or the vehicle is not being operatedunder predictive conditions, the system can nevertheless operate thecooling system based upon instantaneous conditions. For example, thethermostat can be opened if the coolant temperature is increasing (e.g.,based on the rate of increasing temperature) before a set point isreached. As another example, during cold engine startup, a minimumcoolant flow rate can be established and maintained with the coolantthermostat closed to increase the initial heating of coolant by theengine.

Although the position estimator, optimizer and instantaneous controllerare depicted in FIG. 4 as discrete blocks, this is not to be construedas a limitation. That is, the functionality of these components can becombined or distributed.

One exemplary control approach for optimizer 320 is illustrated inconnection with FIG. 5. The approach starts at block 400 in FIG. 5. Fromblock 400 a block 404 is reached at which the route is established(e.g., by user input) or a segment of a route is predicted. For example,the exact route may not have been established, such as by a driver. Insuch a case, a predictive route approach can be used with a next segmentof a route being predicted from a known position and direction oftravel. At block 406 a determination is made as to whether the vehicleposition is known (e.g., whether a GPS signal is available). If theanswer is no, a block 408 is reached and control of thermal componentsto the vehicle are based upon instantaneous operating conditions,desirably based both on vehicle parameters and environmental conditions.

Assuming at block 406 it is determined that the vehicle position isknown, a yes branch from block 406 is followed to a block 409 where adetermination is made as to whether the terrain information isavailable. If the answer is no, the block 408 is again reached. On theother hand, if at block 408 the answer is yes, a block 410 is reachedwhere a determination is made of whether the vehicle is being operatedunder predictive conditions. One specific example is to determinewhether the vehicle is being operated under cruise control, whichenhances the predictability of how the engine will operate. It isexpected that sufficient predictability can also be determined to existwhere a predictive model or driver profile for the vehicle driver isavailable. From block 410, a block 411 is reached. At block 411 aprediction horizon (e.g., an upcoming route segment) is obtained and atblock 412 the grade information is established across the predictionhorizon (based for example upon elevation changes in the map applicableto the prediction horizon). If the route is known or no exits exist forsuccessive prediction horizons, successive prediction horizons can beobtained and processed at a given time. At block 414, the engine heatrejection across the prediction horizon is estimated and block 416 adesired engine temperature profile across the prediction horizon isdetermined. At block 418 control inputs are determined for thermalcomponents across the prediction horizon to cause the vehicle to operatesuch that the engine temperature matches the desired engine temperatureprofile. By match, it is meant that the actual engine temperatureclosely approximates the actual optimum temperature across theprediction horizon.

The control inputs are then delivered to the thermal components atappropriate times as the vehicle traverses the prediction horizon so asto control the components to achieve a match of the actual enginetemperature to the optimized engine temperature. Feedback is providedsuch that the control inputs can be adjusted, at block 422, in the eventinstantaneous vehicle operating conditions indicate such adjustments areneeded (e.g., the liquid coolant is approaching its maximum allowedtemperature). From block 422, a block 430 is reached where adetermination is made as to whether the prediction horizon extends tothe end of the route. If the answer is yes, the vehicle has reached itsdestination. If the answer is no, the block 406 is again reached and theprocess continues for the next prediction horizon. It should be notedthat, if the route is known or there are no road exits from the roadover a plurality of successive prediction windows, plural predictionhorizons for a route can be processed at one time to provide controlinputs for system components for plural predictive windows as thevehicle travels along the route. Alternatively, the prediction horizonsmay be processed in series with the next prediction horizon beingprocessed following the processing of the preceding prediction horizonand while control inputs for the preceding prediction horizon are beingdelivered to the thermal components.

As another more detailed example, the following should be considered.

Consider a thermal cooling system with the following electricalcomponents:

-   -   Electric Coolant Pump    -   Electric Coolant Thermostat        System Modeling:        Force balance at vehicle center of mass: (Longitudinal        Dynamics):        Ma=F _(fueling) −F _(engine friction) −F _(engine/service brake)        −F _(Inertial) −F _(Drag) −F _(Roll) −F _(Grade) −F _(Aux)        Internal Forces:        F_(fueling)=ηkT_(e)        F_(Aux)=ηkT_(Aux)        F _(engine friction) =f(ω)        F _(engine brake) =ηkT _(engine brake) +F _(service brake)

$F_{Intertial} = {{\eta\; J_{eng}k^{2}a} + {\frac{J_{wheels}}{r_{wheels}^{2}}a}}$$k = {\frac{{engine}\mspace{14mu}{speed}}{{vehicle}\mspace{14mu}{speed}} \approx \frac{n_{drive}n_{transmission}}{r_{wheels}}}$External Forces:

$\begin{matrix}{F_{Drag} = \frac{c_{air}A_{L}{\rho\left( {v + V_{wind}} \right)}^{2}}{2}} \\{= {C_{Drag}\left( {v + V_{wind}} \right)}^{2}}\end{matrix}$F_(Grade)=Mg sin θF_(Roll)=MgC_(rr) cos θFull Dynamics:

$\begin{matrix}{{M_{eff}\overset{.}{v}} = {{\eta\;{kT}_{e}} - {C_{drag}\left( {v + V_{wind}} \right)}^{2} - {{Mg}\;\sin\;\theta} - {{MgC}_{rr}\cos\;\theta} -}} \\{F_{\underset{friction}{engine}} - F_{\underset{\underset{brake}{service}}{{engine}/}} - {\eta\;{kT}_{Aux}}} \\{M_{eff} = {M + \left( {{\eta\; J_{eng}k^{2}} + \frac{J_{wheels}}{r_{wheels}^{2}}} \right)}}\end{matrix}$System Equation:

${m\frac{\mathbb{d}v}{\mathbb{d}t}} = {f\left( {{\theta(x)},v,T_{end},T_{Aux}} \right)}$whereθ(x)=Road Gradeν=Vehicle VelocityT_(e)=Engine TorqueT_(Aux)=Auxiliary Torque

The above system equation shows that the vehicle acceleration is adirect function of the grade, current velocity, engine torque, andauxiliary torque. The engine wall temperature and engine coolanttemperature at any instant can be expressed as a function of the currentengine speed, engine torque, vehicle velocity, and ambient temperature.{dot over (T)} _(w) =f ₁(N _(e) ,T _(e) ,ν,T _(amb))T _(c,out) ^(•) =f ₂(T _(c,in) ,T _(w) ,{dot over (m)} _(c))whereN_(e) is the engine speedT_(amb) is the ambient temperatureT_(c,in) is the engine inlet coolant temperatureT_(w) is the engine wall temperature{dot over (m)}_(c) is the coolant flow rateCost Function:

-   -   Minimize the energy consumed by the coolant pump. (J_(pump))

The energy consumed by the coolant pump will be minimal if the coolantflow rate is minimized.

${\overset{.}{m}}_{c} = {f\left( u_{pump} \right)}$$J_{pump} = {\lambda_{1}{\int_{t_{0}}^{t}{\left( {\overset{.}{m}}_{c} \right){\mathbb{d}t}}}}$

-   -   Minimize fan activation by controlling the coolant temperature        below the fan activation temperature and the maximum allowable        limit to prevent engine speed and torque derates. Also maintain        the engine wall temperature within the maximum allowable limit.        (J_(bound))

${\begin{matrix}{J_{bound} = {\lambda_{2}{\int_{t_{0}}^{t}{\left( {T_{c,{out}} - T_{c,{fan}}} \right)^{2}{\sigma\left( {T_{c,{out}}T_{c,{fan}}} \right)}{\mathbb{d}t}}}}} \\{{\lambda_{3}{\int_{t_{0}}^{t}{\left( {T_{c,{out}} - T_{c,\max}} \right)^{2}{\sigma\left( {T_{c,{out}}T_{c,\max}} \right)}{\mathbb{d}t}}}} +} \\{\lambda_{4}{\int_{t_{0}}^{t}{\left( {T_{w} - T_{w,\max}} \right)^{2}{\sigma\left( {T_{w}T_{w,\max}} \right)}{\mathbb{d}t}}}}\end{matrix} + {\sigma(\xi)}} = \begin{Bmatrix}1 & {\xi \geq 0} \\0 & {\xi < 0}\end{Bmatrix}$

-   -   Minimize engine wall temperature variation from reference.        (J_(wall))

J_(wall) = λ₅∫_(t₀)^(t)(T_(w, des) − T_(w))²𝕕t

-   -   Minimize coolant temperature variation from reference.        (J_(coolant))

J_(coolant) = λ₆∫_(t₀)^(t)(T_(c, out, des) − t_(c, out))²𝕕tLumped Cost Function to be minimized:J=J _(pump) +J _(bound) +J _(wall) +J _(coolant)

The objective in this example is to find the thermostat and coolant pumpcommands to minimize the Lumped Cost Function across the predictionhorizon, and then the values of the Desired Engine Wall and Coolanttemperatures that correspond to these optimal control commands.

Thus, in accordance with the above example, control of the components isinstituted in order to minimize a cost function that, in the illustratedexample, is comprised of a plurality of lumped cost functions. Thesespecific cost functions of this example are: J_(pump); J_(bound),J_(wall); and J_(coolant). Different cost functions can also beutilized. In addition, one or more of these described cost functions canbe utilized even though a more desirable approach is to utilize at leastthese four cost functions in the analysis.

Additional examples are illustrated in connection with FIGS. 6-9. In theexamples of FIGS. 6-9, hypothetical examples, an instantaneous controlapproach has been illustrated without using the predictive control basedon knowledge of upcoming terrain changes.

-   -   Notations used in FIGS. 6-9 examples:        -   T_(max/min)=max/min coolant temperature allowed in the            cooling system, e.g., ΔT˜10° C.        -   T_(FAN max/min)=max/min coolant temperature for turning            on/off engine fan        -   T_(CP max/min)=max/min coolant temperature for speed            increase/decrease @ electrical cooling pump        -   T_(TH max/min)=max/min coolant temperature for            opening/closing the electrical thermostat valve        -   T_(SH max/min)=max/min coolant temperature for            opening/closing the grille shutter    -   Further explanation of examples of FIGS. 6-9:        -   For the high coolant thermostat temperature (see the            cross-hatched rectangular area), there is desirably an            equivalent range of values instead of a constant threshold            value (e.g., T_(max)=85° C. for 10% opening; T_(max)=86° C.            for 50%; T_(max)=87° C. for 100% opening)        -   Similar ranges of values are desirably used for high            temperature values for an electric cooling pump; not            represented here for convenience.    -   The heavy black line trajectory in FIGS. 6-8 represents the        coolant temperature variation in a system (New System Example)        with an electrically controlled coolant pump, electrically        controlled fan and electrically controlled coolant thermostat.    -   The black dotted trajectory in FIGS. 6-8 represent the coolant        temperature variation in a system using a gear driven coolant        pump and fan controlled by upper and lower coolant temperature        set points (Legacy System)    -   The examples of FIGS. 6-8 are of an instantaneous control        approach; no predictive control is included in these figures        (e.g., terrain and/or position information is lacking or not        used).    -   FIG. 6; an example of a Steep Uphill Scenario 1 (grade>3%)        -   FIG. 6 shows two fan events (fan switched on twice) in the            Legacy System vs. one fan event in the New System Example).        -   In FIG. 6, the Legacy System behavior at the beginning of            the climb is identical to the behavior of the New System            Example.    -   FIG. 7; An example of a Steep Uphill Scenario 2 followed by a        downgrade.    -   FIG. 8; Rolling Hills Scenario 3 (grade varies between 0 and        3%/+/−).        -   Fan events (turning on the fan) can easily be eliminated in            the FIGS. 7 and 8 examples of the New System Example            operation by varying the operation of the coolant thermostat            and by changing (e.g., continuously varying) the rate at            which the engine coolant pump is pumping coolant through the            radiator of the New System Example.

The predictive operating mode (e.g., using knowledge about incominggrade facilitates improved control of electrically controlledauxiliaries to keep the coolant temperature in a desired highertemperature range (high-end values; e.g., no more than 10° C.variation).

One exemplary front grille shutter system, if used, has a very simplelogic: if ambient temperatures are under T_(min), then desirably theshutter system is operated such that the front grille is closed (e.g.,completely closed). If the ambient temperature is too high (e.g., at orabove a threshold), desirably the shutter system is operated to open thefront grille (e.g., completely opened). Desirably, although this can bevaried, the shutter system is not operated to open when driving, unlessambient temperatures vary significantly or opening is required toenhance engine cooling. Also, when there is a fan event (the fan isswitched on), the shutter is desirably operated to be fully open,otherwise switching the fan on is inefficient.

Having illustrated and described the principles of our invention withrespect to several embodiments, it should be apparent to those ofordinary skill in the art that the embodiments may be modified inarrangement and detail without departing from the inventive principlesdisclosed herein. Thus, for example, the disclosure encompasses a systemoperable based upon either or both (a) instantaneous conditions withoutpredictive information; and (b) predictive information. We claim as ourinvention all such modifications as fall within the scope of thefollowing claims.

1. A method of operating a vehicle having a vehicle fan for assisting inthe cooling of liquid coolant circulating in a vehicle engine coolingsystem, the method comprising: under first vehicle operating conditions,turning on the vehicle fan when the coolant temperature reaches a firstcoolant temperature below a maximum coolant temperature; and undersecond vehicle operating conditions wherein the vehicle is approachingthe crest of a hill, preventing the operation of the vehicle fan eventhough the coolant temperature has reached or exceeded the first coolanttemperature and is below the maximum coolant temperature.
 2. A methodaccording to claim 1 comprising removing additional heat from thecoolant in anticipation of the beginning of the hill.
 3. A method ofoperating a vehicle fan and a coolant pump for assisting in the coolingof coolant liquid being circulated by the coolant pump in a vehicleengine cooling system, the method comprising: under first vehicleoperating conditions, operating the coolant pump to pump coolant atleast at a first rate greater than a minimum coolant pumping rate whenthe coolant temperature reaches a first temperature below a maximumcoolant temperature; under second vehicle operating conditions whereinthe vehicle is going down a grade, operating the coolant pump to pumpcoolant at least at the first rate even though the coolant temperatureis below the first temperature to provide additional cooling of thecoolant fluid prior to climbing a grade.
 4. A method according to claim3 comprising; under third vehicle operating conditions, turning on thefan and operating the coolant pump at least at the first rate when thecoolant temperature reaches a second temperature above the firsttemperature and below the maximum coolant temperature; and under fourthvehicle operating conditions wherein the vehicle is going down a grade,turning on the fan and operating the coolant pump at least at the firstrate even though the coolant temperature is below the secondtemperature.
 5. A method of operating a vehicle engine cooling system ofa vehicle traveling along a route, the cooling system having coolingfluid circulating in the cooling system, the method comprising:determining the presence of an upcoming uphill grade in a section of aroute that has yet to be traversed by the vehicle; and operating thecooling system to remove a first quantity of heat from the cooling fluidprior to reaching the upcoming uphill grade, the first quantity of heatbeing greater than the quantity of heat that is removed by the coolingsystem in the absence of the upcoming uphill grade.
 6. A method ofoperating a vehicle engine cooling system of a vehicle traveling along aroute, the cooling system having cooling fluid circulating in thecooling system, the method comprising: determining a desired vehicleengine temperature profile correlated to positions along a section ofthe route; and controlling the operation of the cooling system to causethe temperature of the vehicle engine to match the desired vehicleengine temperature profile when the vehicle travels along the section ofthe route.
 7. A method according to claim 6 wherein the act ofdetermining comprises determining a desired vehicle engine temperatureprofile based at least in part upon existing vehicle operatingconditions and the elevation at various locations along the section ofthe vehicle route.
 8. A method according to claim 6 wherein the enginetemperature profile is at a substantially constant temperature for agiven section of the route for which (a) the elevation is unchangedthroughout the given section of the route; and (b) the elevation isunchanged in both the section of the route immediately prior to thegiven section and immediately following the given section.
 9. A methodaccording to claim 8 wherein the substantially constant temperature iswithin about ten degrees C.° of the maximum allowable engine operatingtemperature.
 10. A method according to claim 6 wherein the act ofdetermining comprises determining a desired engine temperature profilebased at least in part as a function of engine speed and engine torque.11. A method according to claim 6 wherein the act of determiningcomprises determining a desired engine temperature profile based atleast in part upon an estimation of the addition of heat to and theremoval of heat from cooling fluid in the cooling system arising fromheating the cooling fluid due to the operation of the engine over theroute section and arising from cooling of the cooling fluid by at leastone cooling component of the cooling system.
 12. A method according toclaim 11 wherein the at least one cooling component comprises at least acooling pump and a radiator fan.
 13. A method according to claim 12wherein the at least one cooling component also comprises a radiatorclosure mechanism operable to selectively block the delivery of air to aradiator of the cooling system.
 14. A method according to claim 6wherein the act of determining comprises determining a desired enginetemperature profile that minimizes at least one cost function.
 15. Amethod of operating a vehicle engine cooling system of a vehicletraveling along a route, the cooling system having cooling fluidcirculating in the cooling system, the method comprising: receivinginformation indicating the presence of upcoming traffic or road workconditions in a section of a route to be traveled by the vehicle thatwould result in a need to slow down the vehicle when such trafficconditions or road work conditions are encountered by the vehicle; andoperating the cooling system to remove a first quantity of heat from thecooling fluid prior to reaching the location of the traffic or roadwork, the first quantity of heat being greater than the quantity of heatthat is removed by the cooling system in the absence of receivinginformation indicating the presence of upcoming traffic or road workconditions.
 16. A vehicle comprising: an engine; a vehicle enginecooling system for receiving and circulating liquid coolant to cool theengine; a vehicle fan operable to assist the cooling of liquid coolantcirculating in the vehicle engine cooling system; the vehicle enginecooling system comprising a coolant pump operable to circulate liquidcoolant within the vehicle engine cooling system; a coolant systemcontroller operable under first vehicle operating conditions to turn onthe vehicle fan when the coolant temperature reaches a first coolanttemperature below a maximum coolant temperature; and the coolant systemcontroller also being operable under second vehicle operating conditionswherein the vehicle is approaching the crest of a hill, to prevent theoperation of the vehicle fan even though the coolant temperature hasreached or exceeded the first coolant temperature and is below themaximum coolant temperature.
 17. A vehicle comprising: an engine; avehicle engine cooling system for receiving and circulating liquidcoolant to cool the engine; a vehicle fan operable to assist the coolingof liquid coolant circulating in the vehicle engine cooling system; thevehicle engine cooling system comprising a coolant pump operable tocirculate liquid coolant within the vehicle engine cooling system; acoolant system controller operable under first vehicle operatingconditions to control the coolant pump to pump coolant at least at afirst rate greater than a minimum coolant pumping rate when the coolanttemperature reaches a first temperature below a maximum coolanttemperature; the coolant system controller also being operable undersecond vehicle operating conditions wherein the vehicle is going down agrade, to control the coolant pump to pump coolant at least at the firstrate even though the coolant temperature is below the first temperatureto provide additional cooling of the coolant fluid prior to climbing agrade.
 18. A vehicle according to claim 17, wherein the coolant systemcontroller is also operable under third vehicle operating conditions toturn on the fan and to control the coolant pump to pump coolant at leastat the first rate when the coolant temperature reaches a secondtemperature above the first temperature and below the maximum coolanttemperature; and the coolant system controller also being operable underforth vehicle operating conditions wherein the vehicle is going down agrade, to turn on the fan and to control the coolant pump to pumpcoolant at least at the first rate even though the coolant temperatureis below the second temperature.
 19. A vehicle comprising: an engine; avehicle engine cooling system for receiving liquid coolant; a coolantpump for circulating coolant liquid through the vehicle cooling systemand engine; the vehicle engine cooling system comprising a fanselectively operable to cool the coolant liquid circulating through thevehicle cooling system; an elevation profile determiner operable todetermine the presence of an upcoming uphill grade in a section of aroute that has yet to be traversed by the vehicle; and a cooling systemcontroller operable to control the cooling system to remove a firstquantity of heat from the coolant liquid prior to reaching the upcominguphill grade, the first quantity of heat being greater than the quantityof heat that is removed by the cooling system in the absence of theupcoming grade.
 20. A vehicle comprising: an engine; a vehicle enginecooling system for circulating cooling fluid to remove heat from theengine, the vehicle engine cooling system comprising at least aplurality of cooling components; a cooling system controller operable todetermine a desired vehicle engine temperature profile correlated topositions along a section of a route to be traveled by the vehicle; thecooling system controller also being operable to control the vehicleengine cooling system to cause the temperature of the vehicle engine tomatch the desired vehicle engine temperature profile when the vehicletravels along the section of the route.
 21. A vehicle according to claim20 wherein the cooling system controller is operable to determine adesired vehicle engine temperature profile based at least in part uponexisting vehicle operating conditions and the elevation at variouslocations along the section of the vehicle route.
 22. A vehicleaccording to claim 20 wherein the controller is operable to determine anengine temperature profile that is at a substantially constanttemperature for a given section of the route for which (a) the elevationis unchanged throughout the given section of the route; and (b) theelevation is unchanged in both the section of the route immediatelyprior to the given section and immediately following the given section.23. A vehicle according to claim 22 wherein the substantially constanttemperature is within about ten degrees C.° of the maximum allowableengine operating temperature.
 24. A vehicle according to claim 20wherein the cooling system controller is operable to determine a desiredengine temperature profile based at least in part as a function ofengine speed and engine torque.
 25. A vehicle according to claim 20wherein the cooling system controller is operable to determine a desiredengine temperature profile based at least in part upon an estimation ofthe addition of heat to and the removal of heat from cooling fluid inthe cooling system arising from heating coolant fluid due to theoperation of the engine over the route section and arising from coolingof the cooling fluid by the cooling components.
 26. A method accordingto claim 25 wherein the plurality of cooling components comprise a leasta cooling pump and a radiator fan.
 27. A method according to claim 26wherein the plurality of cooling components also comprise a radiatorclosure mechanism operable to selectively block the delivery of air to aradiator of the cooling system.
 28. A method according to claim 20wherein the cooling system controller is operable to determine a desiredengine temperature profile that minimizes at least one cost function.29. A vehicle comprising: an engine; a vehicle engine cooling system forreceiving and circulating liquid coolant to cool the engine; the vehicleengine cooling system comprising at least a first cooling componentcomprising a vehicle fan operable to assist the cooling of liquidcoolant circulating in the vehicle engine cooling system; the vehicleengine cooling system comprising at least a second cooling componentcomprising a coolant pump operable to circulate liquid coolant withinthe cooling system; the vehicle comprising a receiver operable toreceive information indicating the presence of upcoming traffic or roadwork conditions in a section of a route to be traveled by the vehiclethat would result in a need to slow down the vehicle when such trafficconditions or road work conditions are encountered by the vehicle; and acooling system controller operable to control the cooling components tocause the vehicle engine cooling system to remove a first quantity ofheat from the cooling fluid prior to reaching the location of thetraffic or road work, the first quantity of heat being greater than thequantity of heat that is removed by the vehicle engine cooling system inthe absence of the traffic or road work.